Data transfer apparatus and data transfer system

ABSTRACT

A data transfer apparatus and a data transfer system are provided that can reduce the cost of installing communication equipment compatible with each of several dissimilar communication protocols in one exchange office and can reduce the cost of constructing the network. The data transfer apparatus includes a data reception device ( 110 ) that receives packets that comply with dissimilar communication protocols from upstream data transfer apparatuses ( 51, 52,  and  53 ); a content data extraction device ( 120 ) that extracts content data included in the packets; a line selection information storage device ( 130 ) that stores the line selection information for selecting communication lines that comply with dissimilar communication protocols; a line selection device ( 140 ) that selects the communication line compatible with content data based on the line selection information; and a data transfer device ( 150 ) that transfers data to downstream data transfer apparatuses ( 61, 62,  and  63 ) that are connected to the communication line that has been selected by the line selection device.

TECHNICAL FIELD

The present invention relates to a data transfer apparatus and datatransfer system that transfer data, and in particular relates to a datatransfer apparatus and a data transfer system that comply with thecommunication protocols that relate to networks. In addition, thepresent invention relates in particular to apparatuses (below referredto as router apparatuses) and network systems in which the switching ofpackets (below, referred to as IP packets) among data transferapparatuses is carried out in compliance with Internet Protocol, and,when the network is constructed by a plurality of router apparatuses,relates to an advantageous technology that is applied to these routerapparatuses.

BACKGROUND ART

As an example of a conventional data transfer apparatus, a data transferapparatus positioned at the edge of a network is known that allocates adifferent light wavelength for each destination address contained in theIP packet, time division multiplexes the allocated light wavelengths,and transmits the optical signal that comprises the data by using thetime division multiplexed light wavelength. Thereby, this data transferapparatus transmits a large amount of data at a high speed andefficiency. (For example, refer to Japanese Unexamined PatentApplication, First Publication, No. 2001-251253, paragraph 33, paragraph43, and FIG. 10.)

As another example of a conventional data transfer apparatus, a datatransfer apparatus is known in which the routing process for IP packetsin which a path is determined when data is transferred based on the IPpacket is integrated with the routing process for the light wavelengthin which the route and the light wavelength are determined when theoptical signal that comprises the data is transmitted based on the lightwavelengths. (For example, refer to Japanese Unexamined PatentApplication, First Publication, No. 2001-53803, paragraphs 17 and 18,and FIG. 1.)

However, currently there is the problem that a high cost forcommunication equipment is incurred when placing in one exchange officethe communication equipment that is compatible with each of thedifferent communication protocols related to the tunneling technologiesfor transferring data efficiently in accordance with the variousservices that provide rapidly spreading VPN (virtual private network)and VLAN (virtual local area network) and the like.

In addition, in recent years large-scale networks have been constructedby connecting the various networks operated by such different groups asindustry, communication carriers and the like. Because large-scalenetworks are constructed by using only the high cost conventional datatransfer apparatuses described above, there is the problem that thecosts incurred to construct the network are high.

In contrast, conventionally MPLS (MultiProtocol Label Switching) isknown as one transfer technology for IP (Internet Protocol) packets.

In networks constructed by router apparatuses that are compatible withMPLS, a label associated with the destination address of the IP packedis attached to the IP packet in an edge router apparatus. Then, a label(output label) added to a transmitted IP packet is found based on thelabel (input label) of the received IP packet in a core router. Finally,after swapping the label, the IP packet is transmitted to the nextrouter apparatus, and a path is formed using the label. Note that anedge router is a router apparatus connected to a network and a terminalthat are not compatible with MPLS and another MPLS network or the like(an external network), and a core router is a router apparatus thatcarries out the transfer of packets in the MPLS network.

In addition, a label hierarchy is created, and by referring to thelabels of the same layer in the network, labeled IP packets are tunneledwithin the network (refer, for example, to Japanese Unexamined PatentApplication, First Publication, No. 2002-44126).

However, in this type of conventional router apparatus, at the same timethat the attachment and swapping of labels is carried out, it isnecessary to add a switching tag to the packet in order to switch theincoming packet within the router device. This switching tag alsorequires searching by the destination address or the label, and thusthere is the problem that the processing load increases. In addition,the cost of the router device increases due to the increase in theprocessing load, and thus there is also the problem that the cost ofconstructing the network becomes high.

Searching by destination address and adding a switching tag forswitching within a router apparatus is similar to the normal transfer ofIP packets.

DISCLOSURE OF INVENTION

In order to solve the problems of the conventional technology describedabove, it is an object of the present invention to provide a datatransfer apparatus, a data transfer system, a router apparatus, and anetwork system that allow a reduction in the network cost.

More concretely, it is an object of the present invention to provide adata transfer apparatus and a data transfer system that reduce the costof installing in one exchange office communication equipment that iscompatible with each of the various dissimilar communication protocolsand reduce the cost for constructing the network.

In addition, it is an object of the present invention to provide arouter apparatus and network system that raise the packet transferefficiency by reducing the processing load, reducing the cost of therouter apparatus, and thereby reduces the cost for constructing thenetwork system, by affixing switching tags to packets in the transferpath order and switching the packets within the router apparatuses insequence according to the switching tags.

These and other objects and novel characteristics of the presentinvention will become clear by the disclosures of this specification andthe attached drawings.

Among the inventions disclosed in the present application, the summaryof a representative invention can be simply explained as follows.

The data transfer apparatus of the present invention is a data transferapparatus that receives data from an adjacent upstream data transferapparatus and transfers the received data to an adjacent downstream datatransfer apparatus, and comprises a data reception device that receivespackets that comply to dissimilar communication protocols from theupstream data transfer apparatus; a content data extraction device thatextracts content data included in a packet received by the datareception device; a line selection information storage device in whichline selection information for selecting one of communication lines thatcomply with dissimilar communication protocols is stored; a lineselection device that selects a communication line corresponding to thecontent data extracted by the content data extraction device based onthe line selection information stored in the line selection informationstorage device; and a data transfer device that transfers the packet tothe downstream data transfer apparatus that is connected to thecommunication line that has been selected by the line selection device.

According to this structure, communication lines that comply withdissimilar communication protocols are selected according to the contentdata included in the packets from an upstream data transfer apparatusthat comply with dissimilar communication protocols, and the data istransferred to a downstream data transfer apparatus connected to theselected communication line. Thereby, it is possible to reduce the costfor installing in one exchange office the communication equipmentcompatible with each of the various dissimilar communication protocols.In addition, because the packets are transferred based on line selectioninformation, it is possible to select the transfer path by whichtransfers the packets will be transferred according to network designthat is carried out by the network administrators.

In addition, the data transfer apparatus of the present invention is adata transfer apparatus that receives data from an adjacent upstreamdata transfer apparatus and transfers the received data to an adjacentdownstream data transfer apparatus, and comprises a data receptiondevice that receives packets that comply to dissimilar communicationprotocols from the upstream data transfer apparatus; and a destinationinformation extraction device that extracts destination information thatrepresents a destination included in a packet that has been received bythe data reception device; a destination selection information storagedevice that stores destination selection information for selecting acommunication line; a destination line selection device that selects acommunication line corresponding to the destination information that hasbeen extracted by the destination information extraction device based onthe destination selection information that is stored in the destinationinformation storage device; a content data extraction device thatextracts content data included in a packet received by the datereception device when a plurality of communication lines have beenselected by the destination selection device; a line selectioninformation storage device that stores line selection information forselecting one of the communication lines that comply with dissimilarcommunication protocols; a line selection device that selects thecommunication line that has been selected by the destination lineselection device or selects a communication line corresponding to thecontent data extracted by the content data extraction device based onthe line selection information stored in the line selection informationstorage device; and a data transfer apparatus that transfers the packetsto the downstream data transfer apparatus connected to the communicationline that has been selected by the line selection device.

According to this structure, even with a network configuration in whichthere are a plurality of transfer paths based on the destinationinformation included in the packet, because the packets are transferredbased on line selection information, it is possible to select thetransfer path for a packet according to the network design carried outby network administrators or the like.

In addition, the data transfer apparatus of the present invention canfurther provide a packet analyzing device that analyzes the packetreceived by the data reception device when the destination addressinformation extracted by the destination information extraction devicerepresents its own address and a line selection information updatingdevice that updates the line selection information stored in the lineselection information storage device based on information that has beenanalyzed by the packet analyzing device.

According to this structure, for example, because the line selectioninformation is updated according to predetermined packets transmittedfrom the server and the user terminal, it is possible to select thetransfer path for the packet automatically in response to the requestsform the server and the user terminal.

In addition, the data transfer apparatus of the present invention canfurther provide a line selection information input device that inputsthe line selection information, and the line selection informationstorage device can store the line selection information input from theline selection information input device.

According to this structure, because the line selection information isinput from an administrative terminal, it is possible to update the lineselection information according to the input from the administrativeterminal.

In addition, in the data transfer apparatus of the present invention,the content data can include virtual private network information thatrepresents a virtual private network.

According to this structure, because packets are transferred accordingto the virtual private network information that represents a virtualprivate network, it is possible to select a transfer path by which thepackets will be transferred according to the services that providevirtual private networks to the users.

This virtual private network information can include VLAN identifiersthat are stipulated in IEEE 802.1Q. Thereby, because packets aretransferred according to VLAN identifiers that are stipulated by IEEE802.1Q, it is possible to select the transfer path by which the packetsare transferred according to services that provide VLAN to the users.

This virtual private network information can include VPN labels thatrepresent the VPN stipulated by RFC 2547. Thereby, because the packetsare transferred according to VPN labels that represent a VPN that isstipulated by RFC 2547, it is possible to select the transfer path bywhich the packets are transferred according to services that provideMPLS-VPN to the users.

This virtual private network information can include VC labels thatrepresent the virtual circuit added to the protocol data unit. Thereby,because packets are transferred according to VC labels that representvirtual circuits added to the protocol data unit, it is possible, forexample, to select the transfer path by which the packets aretransferred according to services that provide VPN that is realized inlayer 2 to the users.

In addition, in the data transfer apparatus of the present invention,the content data can include logical line information that represents alogical line.

According to this structure, because the packets are transferredaccording to the logical line information that represents logical lines,it is possible to select a transfer path by which the packets aretransferred according to services that provide logical lines to theusers.

In addition, the data transfer system of the present invention is a datatransfer system in which a data transfer apparatus described abovetransfers data to another data transfer apparatus described above usinga relay method.

According to this structure, because a network construction becomespossible that does not use only expensive conventional data transferapparatuses, it is possible to reduce the cost for constructing thenetwork.

An edge router apparatus according to a first aspect of the presentinvention is an edge router apparatus that is disposed at a connectionbetween a network and the outside of the network, receives a packet fromthe outside of the network and transfers the packet to a routerapparatus within the network, or transmits a packet from a routerapparatus within the network to the outside of the network, andcomprises: a switching information calculation device that obtainsswitching information for switching the received packet at each routerapparatus positioned along a transfer path of the received packet withinthe network based on a destination address of the packet received fromthe outside of the network; and a transmitting device that affixes tothe received packet the switching information obtained by the switchinginformation calculation device in a transfer path order, and transmitsthe received packet to which the switching information has been affixedto a transfer destination router apparatus.

According to this structure, in the edge router apparatus, at eachrouter apparatus positioned along the transfer path of the receivedpacket in the network, the switching information for switching thereceived packet is affixed to the received packet in the transfer pathorder.

Therefore, in each of the router apparatuses, because it is possible tocarry out switching by using switching information that has been affixedto the packet, in the core router, it is not necessary to carry out asearch of the switching information, it is possible to reduce theprocessing load, and it is possible to increase the transfer efficiency.

In addition to the structure of the edge router apparatus of the firstaspect described above, the edge router apparatus according to a secondaspect of the invention further provides a routing table that storesswitching information for switching the packet at each router apparatuspositioned along a transfer path of the packet in the network up to theother network for each network address of the other network, uses adestination address of the packet received from the other network,searches the routing table, and obtains the switching information forswitching the received packet at each router apparatus positioned alongthe transfer path of the received packet within the network up to anetwork specified by the destination address. According to thisstructure, in each of the router apparatuses positioned along thetransfer path of the received packet in the network, the switchinginformation for switching packets is stored as a routing table, and thepackets are transferred by using the path set in the routing table.Therefore, it is possible to find the switching information simply, andit becomes possible to reduce the processing load. As a result, it ispossible to reduce the cost of the network that includes routerapparatuses.

In addition to the structure of the edge router apparatus of the secondaspect described above, an edge router apparatus according to a thirdaspect of the present invention can provide a data input apparatus forsetting the switching information in the routing table. According tothis structure, the routing table can be set by the data inputapparatus. Thereby, it becomes possible to carry out the setting of therouting table simply. As a result, it is possible to reduce the cost ofthe network that includes router apparatuses.

The core router apparatus of the present invention is a core apparatusthat receives and transfers a packet to which switching information hasbeen affixed for switching the packet, and switches the received packetby the core router apparatus itself based on the switching informationattached to the received packet, and transmits a packet that has had theswitching information used by the core router apparatus itself deleted.

According to this structure, packets are switched based on the switchinginformation affixed to the packet, and the packets are transferred afterthe switching information that has been used has been deleted.

The network system according to a first aspect of the present inventionprovides the edge router apparatus according to the first aspect and thecore router apparatus described above.

According to this structure, in the edge router apparatus, at each ofthe router apparatuses positioned along the transfer path of thereceived packet in the network, the switching information for switchingthe packets is affixed in the transfer path order, and in the corerouter apparatus, the switching of the packet is carried out using theswitching information affixed to the packet, and the packet istransferred after the used switching information has been deleted inorder.

Therefore, in the edge router apparatus, the packets are switched andtransferred depending on the affixed switching information.

The network system according to a second aspect of the present inventionprovides the edge router apparatus according to the second aspect andthe core router apparatus described above.

According to this structure, in the edge router apparatus, at each ofthe router apparatuses positioned along the transfer path of thereceived packet in the network, by using the routing table, switchinginformation for switching the received packet is affixed to the receivedpacket, and in the core router apparatus, switching of the packets iscarried out by using the switching information affixed to the packet,and the packets are transferred after the used switching information isdeleted in order. Therefore, packets are switched and transferredaccording to the switching information in the routing table that isstored in the edge router apparatus.

In addition to the structure of the network system described above, theedge router apparatus can provide a data input apparatus for setting theswitching information in the routing table. According to this structure,the routing table can be set by using the data input apparatus. Thereby,it becomes possible to carry out the setting of the routing tablesimply.

In addition to the structure of the network system described above, aspath information, the edge router apparatus reports to a core routerapparatus or another edge router apparatus connected to the edge routerapparatus itself a network address of the other network connected to theedge router apparatus itself and switching information to the othernetwork, and the core router apparatus that has received this pathinformation affixes to the received path information the switchinginformation to a core router apparatus or an edge router apparatus thattransmits this path information. The path information that has had theswitching information affixed is reported to core router apparatuses andedge router apparatuses other than the edge router apparatus or the corerouter apparatus that have transmitted this path information among corerouter apparatuses and edge router apparatuses connected to the corerouter apparatus itself. The edge router apparatus that has receivedthis path information can create the routing table by using thisreceived path information.

According to this structure, the packets follow the path from one edgerouter apparatus to another edge router apparatus in reverse order whilethe switching information is sequentially added to the packets, andthereby the switching information is reported to another edge router anda routing table is created. In this manner, by creating a routing tableby reporting the information between router apparatuses, it becomespossible to set the routing table automatically.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the system structure of the datatransfer system of the first embodiment of the present invention.

FIG. 2 is a block diagram showing the schematic structure of the datatransfer apparatus of the first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the data transferapparatus of the first embodiment of the present invention.

FIG. 4 is a block diagram showing the system construction of the datatransfer system of the second embodiment of the present invention.

FIG. 5 is a block diagram showing the schematic structure of the datatransfer apparatus of the second embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the data transferapparatus of the second embodiment of the present invention.

FIG. 7 is a block diagram showing the system structure of the datatransfer system of the third embodiment of the present invention.

FIG. 8 is a block diagram showing the schematic structure of the datatransfer apparatus of the third embodiment of the present invention.

FIG. 9 is a flowchart showing the operation of the data transferapparatus of the third embodiment of the present invention.

FIG. 10A to FIG. 10C are diagrams showing the packet structure thatshows the network information for a virtual private network.

FIG. 11 is a block diagram showing the schematic structure of the routerapparatus of the fourth embodiment of the present invention.

FIG. 12 is a block diagram showing the schematic structure of the firstline interface unit shown in FIG. 11.

FIG. 13 is a block diagram showing the schematic structure of the secondline interface unit shown in FIG. 11.

FIG. 14 is a drawing that shows the content of the routing table storedin the data memory unit shown in FIG. 12.

FIG. 15 is a drawing showing the format of a packet that is input intothe switching unit shown in FIG. 11.

BEST MODE FOR CARRYING OUT THE INVENTION

Below, embodiments of the present invention will be explained withreference to the figures.

Note that in all the figures for explaining the embodiments, partshaving the same function are denoted by the same reference numeral, andrepetition of the explanation thereof has been omitted.

First Embodiment

FIG. 1 is a block diagram showing the system structure of the datatransfer system of the first embodiment of the present invention.

As shown in FIG. 1, although the data transfer system 41 of the presentembodiment is formed so as to include a plurality of data transferapparatuses 100, the data transfer device 41 can be formed by only onedata transfer apparatus 100. In addition, the data transfer system 41can form a backbone network, and the backbone network connects toexternal networks including a layer 1 network 10, a layer 2 network 20,and a layer 3 network 30.

The layer 1 network 10 is formed so as to include the upstream datatransfer apparatus 51 and the downstream data transfer apparatus 61.

Note that the term “upstream data transfer apparatus” denotes a datatransfer apparatus that transmits received data when viewed from thedata transfer apparatus that receives data. The term “downstream datatransfer apparatus” denotes the data transfer apparatus that receivestransmitted data when viewed from the data transfer apparatus thattransmits data.

The upstream data transfer apparatus 51 and the downstream data transferapparatus 61 comply with well-known communication protocols such as WDM(wavelength division multiplexing), determine a path and a lightwavelength when transmitting an optical signal that comprises data basedon the light wavelengths, and transmit the optical signal based on thedetermined path and light wavelength.

In addition, data can be transferred based on packets that comply withwell-known protocols such as SDH (Synchronous Digital Hierarchy) and ATM(Asynchronous Transfer Mode). In the upstream data transfer apparatus 51and the downstream data transfer apparatus 61, these communicationprotocols can be mixed, and data can be transferred based on packetsthat comply with their respective communication protocols.

The layer 2 network 20 is formed so as to include an upstream datatransfer apparatus 52 and a downstream data transfer apparatus 62.

The upstream data transfer apparatus 52 and the downstream data transferapparatus 62 transfer data based on packets that comply with well-knowncommunication protocols such as Ethernet.

In addition, the upstream data transfer apparatus 52 and the downstreamdata transfer apparatus 62 can transfer data based on packets thatcomply with well-known communication protocols such as MPLS(MultiProtocol Label Switching). In the upstream data transfer apparatus52 and the downstream data transfer apparatus 62, these communicationprotocols can be mixed, and data can be transferred based on packetsthat comply with their respective communication protocols.

The layer 3 network 30 is formed so as to include an upstream datatransfer apparatus 53 and a downstream data transfer apparatus 63.

The upstream data transfer apparatus 53 and the downstream data transferapparatus 63 determine the path when data is transferred based onpackets (below, referred to as IP packets) that comply with the InternetProtocol, and transmit the IP packets on the determined path.

FIG. 2 is a block diagram showing the schematic structure of the datatransfer apparatus in the first embodiment of the present invention.

As shown in FIG. 2, the data transfer apparatus 100 of the presentembodiment provides a data reception device 110, a content dataextraction device 120, a line selection information storage device 130,a line selection device 140, an optical space switch 141, a datatransfer device 150, and a line selection information input device 160.

The data reception device 110 includes a line interface 111 thatreceives an optical signal transmitted from the upstream data transferapparatus 51 that forms the layer 1 network 10; a line interface 112that receives packets that has been transmitted from the upstream datatransfer apparatus 52 that forms the layer 2 network 20 and comply withthe Ethernet; a line interface 113 receives packets that has beentransmitted from the upstream data transfer apparatus 52 that forms thelayer 2 network 20 and comply with MPLS; and a line interface 114 thatreceives IP packets transmitted from the upstream data transferapparatus 53 that forms the layer 3 network.

In addition, the line interface 111 transmits a predetermined opticalsignal to the optical space switch 141 based on the light wavelengththat forms the received optical signal. Note that in FIG. 2, althoughfour line interfaces are shown, the number of line interfaces is notlimited to four.

The data reception device 110 receives data that comply with dissimilarcommunication protocols via the line interface 111, the line interface112, the line interface 113, and the line interface 114, and the packetscomprising the received data are output to the content data extractiondevice 120.

The packets output from the data reception device 110 are input into thecontent data extraction device 120, the content data extraction device120 extracts the content data that is included in the input packet, andthe extracted content data or a packet corresponding to the extractedcontent data is output to the line selection device 140.

For example, virtual private network information that represents avirtual private network, or logical line information that represents alogical line such as an LSP (Label Switched Path) in MPLS (MultiProtocolLabel Switching) or a VP (Virtual Path) and VC (Virtual Channel) in ATM(Asynchronous Transfer Mode) are included in the content data.

The line selection information storage device 130 stores the lineselection information for selecting the communication lines that complywith dissimilar communication protocols.

Line selection information that is output from the line selectioninformation input device 160 can be input into this line selectioninformation storage device 130, and the line selection informationstorage device 130 can store the input line selection information.

The line selection information includes, for example, the content dataincluded in the packet and information that represents the associationbetween the identifiers of the line interfaces for transmitting packets.

Note that virtual private network information is included in the contentdata, and FIG. 10A to FIG. 10C are packet structure diagrams showing thevirtual private network information.

The virtual private network information included in the packet 1000includes, for example, as shown in FIG. 10A, a VLAN identifier 1001 thatis stipulated in IEEE 802.1Q (Institute of Electrical and ElectronicsEngineers); as shown in FIG. 10B, a VPN label 1002 that represents theVPN (virtual private network) stipulated in RFC 2547 (Request forComments); and as shown in FIG. 10C, a VC label 1003 that represents avirtual circuit (VC) affixed to a protocol data unit (PDU).

Note that the PDU shown in FIG. 10C includes data stipulated in IEEE802.3 and data stipulated in IEEE 802.1Q, and the tunneling headerincludes a shim header and the like.

Here, Table 1 shows an example of the line selection information thatrepresents the association between the virtual private networkinformation and the identifiers of the line interfaces. Note that theline interfaces comprises a communication line.

TABLE 1 Content data (virtual private network information) Lineinterface VLAN identifier: from 10 to 20 Line interface #151 VPN label:from 101 to 200 Line interface #152 VC label: from 101 to 200 Lineinterface #153 Other packets Line interface #154

In addition, the logical line information that represents the logicalline is included in the content data, and the VP (Virtual Path), the VC(Virtual Channel), and the LSP (Label Switched Path), which istransferred based on the label that forms the shim header, are includedin the logical line.

Here, Table 2 shows an example of the line selection information thatrepresents the association between the logical line information and theidentifiers of the line interfaces.

TABLE 2 Content data (logical line information) Line interface Labelthat forms the shim header: from 1 to 5 Line interface #151 VP: from 10to 20 Line interface #152 VP = 1 and VC: from 101 to 200 Line interface#153 Other packets Line interface #154

The content data and the packets output from the content data extractiondevice 120 are input into the line selection device 140.

The line selection device 140 selects the line interface correspondingto the input content data based on the line selection information storedin the line selection information storage device 130, and the lineselection identifiers that represent the selected line interface and theinput packets are output to the data transfer device 150.

For example, as shown in Table 1, in the case that the input is a packet1000 in which the value represented by the VLAN identifier 1001 is from10 to 20, the line selection device 140 outputs the selected lineidentifier that represents the line interface 151 and the packet 1000 tothe data transfer device 150.

In addition, in the case that the input is a packet 1000 in which thevalue represented by the VPN label 1002 is from 101 to 200, the lineselection device 140 outputs the selected line identifier thatrepresents the line interface 152 and the packet 1000 to the datatransfer device 150.

In addition, in the case that the input is a packet 1000 in which thevalue represented by the VC label 1003 is from 101 to 200, the lineselection device 140 outputs the selected line identifier thatrepresents the line interface 153 and the packet 1000 to the datatransfer device 150.

Furthermore, in the case that the input is a packet in which the valuerepresented by the VLAN identifier 1001 outside the range from 10 to 20,a packet in which the value represented by the VPN label 1002 is outsidethe range from 101 to 200, a packet in which the value represented bythe VC label 1003 is outside the range from 101 to 200, or a packet 1000that does not include virtual private network information in the contentdata, the line selection device 140 outputs the selected line identifierrepresenting the line interface 154 and the packet 1000 to the datatransfer device 150.

In addition, as shown in Table 2, in the case that the input is a packetin which the value represented by the label that forms the shim headeris from 1 to 5, the line selection device 140 outputs the selected lineidentifier representing the line interface 151 and the packet to thedata transfer device 150.

In addition, in the case that the input is a cell in which the valuerepresented by a VP is from 10 to 20, the line selection device 140outputs a selected line identifier that represents the line interface152 and the cell to the data transfer device 150. Note that according tothe regulations of ATM, a packet that is formed by a 53 octets isreferred to as a cell.

In addition, in the case that the input is a cell in which the valuerepresented by the VP is 1 and the value represented by the VC is from101 to 200, the line selection device 140 outputs a selected lineidentifier that represents the line interface 153 and the cell to thedata transfer device 150.

Furthermore, in the case that the input is a packet in which the valuerepresented by the label that forms the shim header is outside a rangefrom 1 to 5, the cell in which the value represented by the VP isoutside a range from 10 to 20, a cell in which the value of VP is 1 andthe value represented by VC is outside a range from 101 to 200, or apacket that does not include logical line information in the contentdata, the line selection device 140 outputs the selected line identifierthat represents the line interface 154 and the packet to the datatransfer device 150.

The identifier of the line interface and packet output from the lineselection device 140 are input into the data transfer device 150, andthe data transfer device 150 transfers the data including of the packetsto the downstream data transfer apparatus 61, the downstream datatransfer apparatus 62, or the downstream data transfer apparatus 63 thatis connected to the communication line indicated by the input selectedline identifier.

The data transfer device 150 includes a switching unit 155, a lineinterface 151, a line interface 152, a line interface 153, and a lineinterface 154.

The selected line identifier and the packet output from the lineselection device 140 are input into the switching unit 155, and theswitching unit 155 outputs the packet to communication line indicated bythe input selected line identifier, that is, any one among the lineinterfaces.

The packets output from the switching unit 155 are input into the lineinterface 151, and the line interface 151 transmits the optical signalthat forms the data including the input packets to the downstream datatransfer apparatus 61.

In addition, the line interface 151 transmits the optical signaltransmitted by the optical space switch 141 to the downstream datatransfer apparatus 61. Note that in FIG. 2, although four lineinterfaces are illustrated, the number of line interfaces is not limitedto four.

The line interface 152 inputs the packets output from the switching unit155, and the line interface 152 transmits the input packets to thedownstream data transfer apparatus 62 in compliance with Ethernet.

The line interface 153 inputs the packets output from the switching unit155, and the line interface 153 transmits the input packets to thedownstream data transfer apparatus 63 in compliance with MPLS.

The packets output from the switching unit 155 are input into the lineinterface 154, and the line interface 154 converts the input packetsinto IP packets and transmits the converted IP packets to the downstreamdata transfer apparatus 64.

The optical space switch 141 receives the optical signal transmitted bythe line interface 111, converts the light wavelength that forms thereceived optical signal, and transmits the optical signal including theconverted light wavelength to the line interface 151.

The line selection information from an administrative terminal 70 isinput into the line selection information input device 160, and theinput line selection information is output to the line selectioninformation storage device 130. Note that according to the presentinvention, the line selection information input device 160 can input theline selection information from the administrative terminal 70 via anadministrative network that is administered by a communication carrieror the like.

Below, the operation of the data transfer apparatus according to thefirst embodiment of the present invention will be explained withreference to FIG. 3.

FIG. 3 is a flowchart showing the operation of the data transferapparatus of the first embodiment of the present invention.

First, the line selection information is input into the line selectioninformation input device 160 via the administrative network from theadministrative terminal 70, and stored in the line selection informationstorage device 130 (step S 101).

In contrast, packets formed by data complying with dissimilarcommunication protocols are received by the data reception device 110via the line interface 111, line interface 112, line interface 113, andthe line interface 114 (step S 102).

When the packets are input into the content data extraction device 120,the content data included in the packet is extracted by the content dataextraction device 120 (step S 103).

Next, when the packets have been input into the line selection device140, the selected line identifier that indicates the line interfaceassociated with the content data is selected by the line selectiondevice 140 based on the line selection information stored in the lineselection information storage device 130 (step S 104).

Next, when the packets are input into the data transfer device 150, thedata including the packets is output to the communication line indicatedby the selected line identifier, that is, any one among the lineinterfaces, by the switching unit 155, and then transferred to adownstream data transfer apparatus (step S 105).

Subsequently, when the data is received by the data transfer apparatus100, the steps from step S 102 to step S 105 are repeated.

Note that in the data transfer system 41 shown in FIG. 1, the data thatis transmitted to the data transfer apparatus 100-1 from the upstreamdata transfer apparatus 51, the upstream data transfer device 52, andthe upstream data transfer apparatus 53 is transferred by using a relaymethod, for example, to the data transfer apparatus 100-2 by the datatransfer apparatus 100-1, transferred to the data transfer apparatus100-3 by the data transfer apparatus 100-2, and then transferred to anyamong the downstream data transfer apparatus 61, downstream datatransfer apparatus 62, or downstream data transfer apparatus 63 by thedata transfer apparatus 100-3.

As explained above, the data transfer apparatus of the first embodimentof the present invention selects communication lines that comply withdissimilar communication protocols depending on the content data, whichin included in data complying with dissimilar protocols, from anupstream data transfer apparatus, and transfers the data to thedownstream transfer apparatus connected to the selected communicationline. Thereby, it is possible to decrease the cost for installingrespective communication equipment for each dissimilar communicationprotocol in one exchange office.

In addition, because packets are transferred based on the line selectioninformation, it is possible to select the transfer path by which thepackets will be transferred depending on network design carried out bythe network administrator or the like.

In addition, because packets are transferred depending on the virtualprivate network information what represents the virtual private network,it is possible to select the transfer path through which the packetswill be transferred depending on the services or the like that providethe virtual private network to the user.

In addition, because packets are transferred depending on the logicalline information that represents the logical line, it is possible toselect the transfer path through which the packets will be transferreddepending on the services or the like that provide the logical line tothe user. For example, because packets are transferred depending on thelabel that represents LSP, it is possible to select the transfer paththrough which the packets will be transferred depending on the servicesor the like that provide LSP to the user.

Furthermore, because packets are transferred depending on VP and VC, itis possible to select the transfer path through which the packets willbe transferred depending on services or the like that provide VP or VCto the user.

In addition, because packets are transferred depending on VLANidentifiers stipulated in IEEE 802.1Q, it is possible to select thetransfer path through which the packets will be transferred depending onservices or the like that provide VLAN to the user.

In addition, because packets are transferred according to VPN labelsthat represent VPN stipulated by RFC 2547, it is possible to select thetransfer path through which the packets will be transferred depending onservices and the like that provide MPLS-VPN to the user.

In addition, because packets are transferred depending on VC labels thatrepresent the virtual circuit added to the protocol data unit, it ispossible, for example, to select the transfer path through which thepackets will be transferred depending on services and the like thatprovide VPN realized in layer 2 to the user.

In addition, because line selection information is input from anadministrative terminal, it is possible to update the line selectioninformation depending on input from the administrative terminal.

In addition, because the data transfer system of the first embodiment ofthe present invention allows network construction without using onlyconventional high cost data transfer apparatuses, it is possible thedecrease the cost of constructing the network.

Second Embodiment

FIG. 4 is a block diagram showing the system configuration for the datatransfer system according to the second embodiment of the presentinvention.

As shown in FIG. 4, the data transfer system 42 of the presentembodiment is formed so as to include a plurality of data transferapparatuses 100 and a data transfer apparatus 200. However, the datatransfer system 42 can be formed by one data transfer apparatus 200 orcan be formed by a data transfer apparatus 200 and other data transferapparatuses. In addition, the data transfer system 42 can form abackbone network, and the backbone network is connected to an externalnetwork including a layer 1 network 10, a layer 2 network 20, and alayer 3 network 30.

FIG. 5 is a block diagram showing the schematic structure of the datatransfer apparatus according to the second embodiment of the presentinvention.

As shown in FIG. 5, the data transfer apparatus 200 of the presentembodiment including a data reception device 110, a content dataextraction device 120, a line selection information storage device 130,a line selection device 240, an optical space switch 141, a datatransfer device 150, a line selection information input device 160, adestination information extraction device 270, a destination selectioninformation storage device 271, and a destination line selection device280.

Note that among the devices that structure the data transfer apparatus200 according to the second embodiment of the present invention, devicesidentical to the devices that form the data transfer apparatus 100 ofthe first embodiment are denoted by identical reference numerals, andthe explanations thereof have been omitted.

The destination information extraction device 270 inputs packets outputfrom the data reception device 110, the destination informationextraction device 270 extracts the destination information thatrepresents the destination included in the input packet, and theextracted destination information and packets are output to thedestination line selection device 280.

The destination selection information storage device 271 stores thedestination selection information for selecting the communication linebased on the destination information. Note that the destinationselection information can be generated in compliance with path controlprotocols such as OSPF (Open Shortest Path First) and can be input fromthe administrative terminal.

An example of the destination selection information that shows theassociation between the destination information and the identifier ofthe line interface is shown in Table 3.

Table 3 shows the identifier of the line interface that corresponds tothe destination IP address (Internet Protocol Address) that representsthe destination. Note that the line interface forms the communicationline.

TABLE 3 Destination IP address Line interface Destination IP address:from 111.0.0.0 to 111.0.0.9 Line interface #151 Line interface #152Destination IP address: from 222.0.0.0 to 222.0.0.9 Line interface #152Destination IP address: from 333.0.0.0 to 333.0.0.9 Line interface #153Other destination IP addresses Line interface #154

For example, the destination information included in the packet is adestination IP address, and in the case that the destination IP addressrepresents “Destination IP address: from 111.0.0.0 to 111.0.0.9”, theline interface 151 and the line interface 152 are selected.

The destination information and the packets output from the destinationinformation extraction device 270 are input into the destination lineselection device 280, and the destination line selection device 280selects the line interface corresponding to the input destinationinformation based on the destination selection information stored in thedestination selection information storage device 271.

In the case that a plurality of line interfaces are selected, thedestination line selection device 280 outputs the input packets to thecontent data extraction device 120.

In the case that a plurality of line interfaces are not selected, thedestination line selection device 280 outputs the selected lineidentifier that represents the selected line interface and the inputpacket to the line selection device 240.

The selected line identifier and the packet output from the destinationline selection device 280 are input into the line selection device 240,and the line selection device 240 outputs the input selected lineidentifier and the input packet to the data transfer device 150.

In addition, the content data and the packets output from the contentdata extraction device 120 are input into the line selection device 240,and the line selection device 240 selects the line interfacecorresponding to the input content data based on the line selectioninformation stored in the line selection information storage device 130,and the selected line identifier that represents the selected lineinterface and the input packet are output to the data transfer device150.

Below, the operation of the data transfer apparatus according to thesecond embodiment of the present invention will be explained withreference to FIG. 6.

FIG. 6 is a flowchart showing the operation of the data transferapparatus according to the second embodiment of the present invention.Note that the operations of the data transfer apparatus 200 of thesecond embodiment of the present invention that are identical to theoperation of the data transfer apparatus of the first embodimentdescribed above are denoted by the same reference symbols, and theirexplanation has been omitted.

First, the destination selection information is generated in compliancewith a path control protocol such as OSPF, and stored in the destinationselection information storage device 271 (step S 201).

When the packets are input into the destination information extractiondevice 270, the destination information included in the packets isextracted by the destination information extraction device 270 (step S202).

Next, when the packets and destination information are input into thedestination line selection device 280, based on the destinationselection information stored in the destination selection informationstorage device 271, the line interface associated with the destinationinformation is selected by the destination line selection device 280(step S 203).

In the case that a plurality of line interfaces have been selected, thepackets are input into the content data extraction device 120 from thedestination line selection device 280. In the case that a plurality ofline interfaces has not been selected, the packets are output from thedestination line selection device 280 to the line selection device 240(step S 204).

Next, when the packets are input into the line selection device 240,based on selected line identifiers and packets output from thedestination line selection device 280 or based on the line selectioninformation stored in the line selection information storage device 130,the line selection identifier that represents the line interfaceassociated with the content data is selected, and the selected lineidentifier that represents the selected line interface and the packetsare output to the data transfer device 150 (step S 205).

Note that in the data transfer system 42 shown in FIG. 4, the datatransmitted from the upstream data transfer apparatus 51, the upstreamdata transfer device 52, or the upstream data transfer apparatus 53 tothe data transfer apparatus 200 is transferred by using a relay method,for example, to the data transfer apparatus 100-2 by the data transferapparatus 200, transferred to the data transfer apparatus 100-3 by thedata transfer apparatus 100-2, and transferred to any among thedownstream data transfer apparatus 61, the downstream data transferapparatus 62, or the downstream data transfer apparatus 63 by the datatransfer apparatus 100-3.

As explained above, the data transfer apparatus according to the secondembodiment of the present invention can select transfer paths forpackets depending on network design carried out by the networkadministrators because the packets are transferred based on lineselection information, even in a network structure in which there are aplurality of transfer paths based on destination information included inthe packets.

In addition, because the data transfer system according to the secondembodiment of the present invention allows network construction withoutusing only conventional high cost data transfer apparatuses, it ispossible the decrease the cost of constructing the network.

Third Embodiment

FIG. 7 is a block diagram showing the system structure of the datatransfer system according to the third embodiment of the presentinvention.

As shown in FIG. 7, the data transfer system 43 of the presentembodiment is formed so as to include a plurality of data transferapparatuses 100 and a data transfer apparatus 300. However, the datatransfer system 43 can be formed by one data transfer apparatus 300, orcan be formed by a data transfer apparatus 300 and other data transferapparatuses. In addition, the data transfer system 43 can form abackbone network, and the backbone network can be connected to anexternal network including a layer 1 network 10, a layer 2 network 20,and a layer 3 network 30.

FIG. 8 is a block diagram showing a schematic structure of the datatransfer apparatus according to the third embodiment of the presentinvention.

As shown in FIG. 8, the data transfer apparatus 300 of the presentembodiment including a data reception device 110, a content dataextraction device 120, a line selection information storage device 130,a line selection device 240, an optical space switch 141, a datatransfer device 150, a line selection information input device 160, adestination information extraction device 370, a destination selectioninformation storage device 271, a destination line selection device 280,a packet analyzing device 390, and a line selection information updatingdevice 391.

Note that among the devices that form the data transfer apparatus 300 ofthe third embodiment of the present invention, devices identical tothose that form the data transfer apparatus 200 of the second embodimentdescribed above are denoted by identical reference numerals and theirexplanation is omitted.

The packets output from the data reception device 110 are input into thedestination information extraction device 370, the destinationinformation extraction device 370 extracts the destination informationthat represents the destination contained in the input packets, and theextracted destination information and the packets are output to thedestination line selection device 280.

In addition, when the extracted destination information represents itsown address, the destination information extraction device 370 outputspackets to the packet analyzing device 390.

For example, when the data transfer apparatus 300's own address is “100”and the destination information is “100”, the destination informationextraction device 370 outputs the packets to the packet analyzing device390.

The packets output from the destination information extraction device370 are input into packet analyzing device 390, the packet analyzingdevice 390 analyzes the input packets, and the analyzed information isoutput to the line selection information updating device 391.

The analyzed information output from the packet analyzing device 390 isinput into the line selection information updating device 391, and theline selection information updating device 391 updates the lineselection information stored in the line selection information storagedevice 130 based on the input analyzed information.

An example of the line selection information updated based on the lineselection information shown in Table 2 is shown in Table 4.

At this time, the content data contained in the packet is a label thatforms a shim header, and in the case that the shim header indicates“label: from 6 to 9”, the packets are transferred via the line interface151.

For example, in the case that a packet transmitted by a predeterminedterminal is transferred via the layer 1 network 10 included in thedownstream data transfer apparatus 61, an updating packet for updatingthe line selection information is transmitted from the server 80, andthe line selection information shown in FIG. 2 is updated as shown inFIG. 4 based on the updating packet.

TABLE 4 Content data (logical line information) Line interface Labelforming the shim header: Line interface #151 from 1 to 5 VP: from 10 to20 Line interface #152 VP = 1 and VC: from 101 to 200 Line interface#153 Other packets Line interface #154 Label forming the shim header:Line interface #151 (updated) from 6 to 9

Below, the operation of the data transfer apparatus according to thethird embodiment of the present invention will be explained withreference to the figures.

FIG. 9 is a flowchart showing the operation of the data transferapparatus according to the third embodiment of the present invention.Note that among the operations of the data transfer apparatus 300according to the third embodiment of the present invention, operationsidentical to those of the data transfer apparatus according to thesecond embodiment described above are denoted by the same referencesymbols, and their explanation is omitted.

First, in the case that the destination information extracted by thedestination information extraction device 370 indicates its owndestination address, the packet is output to the packet analyzing device390 by the destination information extraction device 370. In the casethat the destination information extracted by the destinationinformation extraction device 370 does not indicate its own address, thepacket is output to the destination line selection device 280 by thedestination information extraction device 370 (step S 301).

Next, when the packet is input into the packet analyzing device 390, thepacket is analyzed by the packet analyzing device 390 (step S 302).

When the analyzed information is input into the line selectioninformation updating device 391, the line selection information isupdated by the line selection information updating device 391 (step S303).

Note that in the data transfer system 43 shown in FIG. 7, the datatransmitted to the data transfer apparatus 300 from the upstream datatransfer apparatus 51, the upstream data transfer device 52, and theupstream data transfer apparatus 53 is transferred by using a relaymethod, for example, to the data transfer apparatus 100-2 by the datatransfer apparatus 300, transferred to the data transfer apparatus 100-3by the data transfer apparatus 100-2, and then transferred to any amongthe downstream data transfer apparatus 61, downstream data transferapparatus 62, or downstream data transfer apparatus 63 by the datatransfer apparatus 100-3.

As explained above, the data transfer apparatus according to the thirdembodiment of the present invention can select the transfer path forpackets automatically depending on the request from the server or theterminal of the user because the line selection information is updateddepending on a predetermined packet that has been transmitted from aserver or the terminal of a user.

In addition, the data transfer system according to the third embodimentof the present invention can decrease the cost for constructing thenetwork because the network construction is possible without using onlyconventional high cost data transfer apparatuses.

Fourth Embodiment

Similar to the first embodiment through the third embodiment describedabove, the fourth embodiment relates to decreasing the network cost, anddecreases the network cost by raising the transfer efficiency of thepackets by reducing the processing load. Below, only the characteristicsof the fourth embodiment will be explained, but it is possible torealize a further reduction in the network cost by applying the firstembodiment through the third embodiment to the present embodiment.

FIG. 11 is a block diagram showing the schematic structure a routerapparatus according to the fourth embodiment of the present invention.

In FIG. 11, the router apparatus according to the present embodiment isconnected to lines and controls the transfer of packets received fromthe lines. In addition, the router apparatus includes a first and secondline interface units (1300 and 1400) that control the transmission ofpackets to the relevant lines; switching unit 1200 that switches thepackets input from the first and second line selection units (1300 and1400) and outputs the packets to a predetermined line interface unit onthe egress; a control unit 1100 that controls the first and second lineinterface units (1300 and 1400) and the switching unit 1200; and a datainput apparatus 1500 for inputting each type of data to the routerapparatus.

The connection between the first and second line interface units (1300and 1400) and the switching unit 1200 is formed so as to be attachableand detachable, and it is possible to connect the switching unit 1200 byfreely combining the line interface units that have dissimilar functionsto form the router apparatus.

FIG. 12 is a block diagram showing a schematic structure of the firstline interface unit 1300 shown in FIG. 11. The first line interface unit1300 can be used in connections outside the network, such as anothernetwork.

As shown in FIG. 12, the first line interface unit 1300 includes aningress line terminator 1310, an ingress packet processing unit 1320, anegress packet processing unit 1340, and an egress line terminator 1350.

The ingress line terminator 1310 is connected to another network via aline, extracts the packets from data received via that line, and theingress packet processing unit 1320 carries out processing such that thepackets extracted by the ingress line terminator 1310 are switched to adesired egress line.

The egress packet processing unit 1340 processes packets switched by theswitching unit 1200 into output packets, and the egress line terminator1350 transmits the packets input from the egress packet processing unit1340 to another network or another router apparatus via a connectedline.

The ingress line terminator 1310 provides an optical/electrical (O/E)converting unit 1311 that converts an optical signal into an electricalsignal and an ingress physical layer processing unit 1312 that extractspackets by carrying out processing for the physical layer on theelectric signal that has been converted by the O/E conversion unit 1311.

The ingress packet processing unit 1320 provides an ingress forwardingprocessing unit (ingress FW processing unit) 1321, a data memory unit1322, a QoS processing unit 1323, and an input switching interface unit(SW-IF) 1324.

Based on the destination address of the input packets, the ingressforwarding processing unit 1321 finds the switching tags in each of therouter apparatuses that are passed through up to the network indicatedby this destination address (including the apparatus itself; that is,each of the routing apparatuses positioned along the transfer path ofthe packets within the network), affixes the apparatus's own switchingtag to the packets, and at the same time, sets the switching tags ofother apparatuses to the label of the respective shim headers, andaffixes the switching tags to the shim headers in the order of thetransfer path order.

The data memory unit 1322 is connected to the ingress forwardingprocessing unit 1321, and for each of the addresses of the othernetworks, stores the switching tags and the like of the routerapparatuses through which the packets pass up to these other networks.

The QoS processing unit 1323 carries out QoS (Quality of Service)processing, such as DiffServ (differentiated services), coloring, andpolicing, on the packets.

The ingress switching interface unit 1324 outputs the packets to theswitching unit 1200.

Egress packet processing unit 1340 provides an egress switchinginterface unit 1342 that outputs the packets output by the switchingunit 1200 to the egress forwarding processing unit 1341 and an egressforwarding processing unit 1341 that outputs the packets to the egressline terminator 1350 after eliminating the switching tags affixed to thepackets.

The egress line terminator 1350 provides an egress physical layerprocessing unit 1352 that converts packets input from the egress packetprocessing unit 1340 into a signal for the physical layer and anelectric/optical (E/O) conversion unit 1351 that converts the signalthat has been converted by the egress physical layer processing unit1352 into an optical signal.

FIG. 13 is a block diagram showing the schematic structure of the secondline interface unit 1400 shown in FIG. 11. The second line interfaceunit 1400 is used at the connections between router apparatuses.

As shown in FIG. 13, the second line interface unit 1400 provides aningress line terminator 1410, an ingress packet processing unit 1420, anegress packet processing unit 1440, and an egress line terminator 1450.

The ingress line terminator 1410 is connected via lines to other routerapparatuses and extracts packets from the data received via these lines.

The ingress packet processing unit 1420 carries out processing in whichthe packets extracted by the ingress line terminator 1410 are switchedto the desired egress line.

The egress packet processing unit 1440 processes the packets switched bythe switching unit 1200 into output packets.

The egress line terminator 1450 transmits the packets input from theegress packet processing unit 1440 to other routing apparatuses via theconnected lines.

The ingress terminator 1410 provides an optical/electrical (O/E)converting unit 1411 that converts an optical signal into an electricalsignal and an ingress physical layer processing unit 1412 that extractspackets by carrying out processing for the physical layer on theelectric signal that has been converted by the O/E converting unit 1411.

The ingress packet processing unit 1420 provides an ingress forwardingprocessing unit 1421 and an ingress switching interface unit 1422 thatoutputs packets to the switching unit 1200.

The ingress forwarding processing unit 1421 affixes the value of thelabel of the top shim header of the input packet to the packet as theapparatus's own switching tag, and at the same time, deletes the topshim header, and moves the next shim header to the top.

The egress packet processing unit 1440 provides an egress switchinginterface unit 1442 that outputs the packet output by the switching unit1220 to the egress forwarding processing unit 1441 and an egressforwarding processing unit 1441 that outputs the packets to the egressline terminator 1450 after deleting the switching tag affixed to thepackets.

The egress line terminator 1450 provides an egress physical layer unit1452 that converts packets input from the egress packet processing unit1440 into a signal for the physical layer, and an electrical/optical(E/O) converting unit 1451 that converts a signal that has beenconverted by the egress physical processing unit 1452 into an opticalsignal.

In addition, the data input apparatus 1500 can be connected to thecontrol unit 1100 of the router apparatus, and as shown in FIG. 14, thedata input apparatus 1500 can store a routing table in which theswitching tags in router apparatuses (including one for the apparatusitself) are arranged for each of the addresses of other networks inorder from the apparatus itself up to the other networks, the routerapparatuses being positioned along the transfer path of the packets inthe networks, in the memory apparatus of the control unit 1100, and atthe initial setting and at the time that the content of the routingtable has been rewritten, the control unit 1100 transfers and stores therouting table in the data memory unit 1322 of the ingress packetprocessing unit 1320 of the first line interface unit 1300.

In a network formed by such routing apparatuses, in order to functionthe router. apparatus as an edge router, the connection lines with othernetworks are accommodated in the first line interface unit 1300, and theconnection line with core router apparatuses in the network areaccommodated in the second line interface unit 1400.

In addition, to function the router apparatus as a core routerapparatus, the connecting lines with other core router apparatuses oredge router apparatuses are accommodated in the second line interfaceunit 1400.

When data from another network is received at the ingress lineterminator 1310 of the first line interface unit 1300 of the edge routerapparatus of the network formed by edge router apparatuses and corerouter apparatuses, the ingress physical layer processing unit 1312extracts the packets from the incoming data, and inputs the packets intothe ingress packet processing unit 1320.

The ingress forwarding processing unit 1321 of the ingress packetprocessing unit 1320 refers to the destination address of the inputpackets, reads the switching label of the line in which the upper bit ofthe destination address of the incoming packets agrees with the value ofthe column of the address prefix by using a routing table (such as thatshown in FIG. 14) stored in the data memory unit 1322, affixes the topswitching tag (in FIG. 14, tag 1 or tag 4) to the packet as theswitching tag of the apparatus itself, sets the switching tags thatfollow this to the label of the format of the shim header of the MPLSprotocol, the set shim headers are arranged in their transfer path orderup to the destination network, these shim headers are affixed to thepackets as stacked shim headers, and the packets are then passed to theQoS processing unit 1323 using a format such as the one shown in FIG.15.

The QoS processing unit 1323 carries out DiffServ (differentiatedservices) processing and well-known QoS processing such as coloring andpolicing on the packets, and outputs the packets to the switching unit1200 via the ingress switching interface unit 1324.

The packets input into the switching unit 1200 are switched by theswitching unit 1200 according to the affixed switching tags, and thepackets are output to the second line interface unit 1400 (transfer to acore router apparatus or an edge router apparatus) or the first lineinterface unit 1300 (returned to the apparatus itself) indicated by theswitching tag.

In the case of transfer to a core router apparatus or an edge routerapparatus, the packets that have been input into the second lineinterface unit 1400 are input into the egress forwarding processing unit1441 via the egress switching interface unit 1442, the apparatus's ownswitching tag is deleted by the egress forwarding processing unit 1441,the packets are converted into signals for the physical layer by theegress line terminator 1450, and the packets are then converted to anoptical signal and delivered to a line.

Similar to the case of the returning to the apparatus itself, theapparatus's own switching tags are deleted from the packets by theegress forwarding processing unit 1341 of the first line interface unit1300, the packets are converted into signals for the physical layer bythe egress line terminator 1350, and then the packets are converted toan optical signal and transmitted to a line.

Next, in the core router apparatus, when the data is received from theedge router apparatus or the core router apparatus in the network by theingress line terminator 1410 of the second line interface unit 1400, theingress physical layer processing unit 1412 extracts the packets fromthe received data, and inputs the packets into the ingress packetprocessing unit 1420.

The ingress forwarding processing unit 1421 of the ingress packetprocessing unit 1420 refers to the top shim header among the stackedshim headers of the input packets, affixes the value in the label ofthis shim header to the packet as the apparatus's own switching tag,carries out editing in which the top shim header is deleted and the nextshim header is moved to the top, and outputs the packets to theswitching unit 1200 via the ingress switching interface unit 1422.

The packets input into the switching unit 1200 are switched by theswitching unit 1200 depending on the affixed switching tags, and thepackets are output to the second line interface unit 1400 (transferredto a core router apparatus or an edge router apparatus) indicated by theswitching tag.

The packets that have been input into the second line interface unit1400 are input into the egress forwarding processing unit 1441 via theegress switching interface unit 1442, the apparatus's own switching tagis deleted by the egress forwarding processing unit 1441, the packetsare converted into signals for the physical layer by the egress lineterminator 1450 and then converted into optical signals, and transmittedto a line.

Next, in the edge router apparatus, when the data from a core routerapparatus or an edge router apparatus in the network is received by theingress line terminator 1410 of the second line interface unit 1400, theingress physical layer processing unit 1412 extracts the packets fromthe incoming data and outputs the packets to the ingress packetprocessing unit 1420.

The ingress forwarding processing unit 1421 of the ingress packetprocessing unit 1420 refers to the shim header at the top of the stackedshim headers of an input packet, affixes a value in the label of thisshim header to the packet as the apparatus's own switching tag, and atthe same time, deletes the shim header at the top and outputs thepackets to the switching unit 1200 via the ingress switching interfaceunit 1422.

The packets input into the switching unit 1200 are switched by theswitching unit 1200 depending on the affixed switching tags, and outputto the first line interface unit 1300 (transmitted to another network)indicated by the switching tags.

The packets input into the first line interface unit 1300 are input intothe egress forwarding processing unit 1341 via the egress switchinginterface unit 1342, the apparatus's own switching tag is deleted by theegress forwarding processing unit 1341, the packets are converted intophysical layer signals by the egress line terminator 1350, and thesignals are converted into optical signals and transmitted to the line.

In this manner, according to the present embodiment, in the edge routerapparatus, switching tags for the router apparatuses (including theapparatus itself) that are passed through up to other networksrepresented by the destination addresses of the packets (the routerapparatuses positioned along the transfer path of the packets in thenetwork) are attached to the packets arranged in the transfer path orderand transmitted. In the core router apparatus, the switching of theapparatus itself is carried out by the tag at the top of the switchingtags affixed to the packets, and the packet is transmitted after thenext tag is moved to the top. Thereby, it is possible to eliminate thesearch processing for the output label and the search processing for theswitching tags based on the input labels of the core router apparatus,and thus it is possible to decrease the processing load.

Moreover, in the present embodiment, the routing table is input by thedata input apparatus 1500, but the routing table can be created byreporting information between the router apparatuses, as in thewell-known OSPF (Open Shortest Path First) protocol.

In this case, an edge router apparatus reports to the core routerapparatus or edge router apparatus connected thereto the network addressof other networks connected to the apparatus itself and the switchinginformation to the other networks as path information, and each of therouter apparatuses affixes switching information (switching tag) forswitching to an adjacent router apparatus at the apparatus itself to thepath information reported from the adjacent router apparatus andnotifies other adjacent router apparatuses.

In addition, the edge router apparatus that has received this pathinformation creates a routing table by using the received pathinformation.

Thereby, in this method, the packets follow the path from one edgerouter apparatus to another edge router apparatus in reverse order whilethe switching information is sequentially added to the packets, andthereby the switching information is reported to another edge router anda routing table is created.

While the invention made by the present inventors has been describedconcretely based on the aforementioned embodiments, it should beunderstood that the present invention is not limited to theseembodiments. Modifications can be made without departing from the spiritof the present invention.

For example, it is possible to implement a further decrease in thenetwork cost by combining the first through third embodiments with thefourth embodiment that are described above.

INDUSTRIAL APPLICABILITY

According to the present invention, communication lines that conform todissimilar communication protocols are selected according to the contentdata included in data conforming to dissimilar communication protocolsfrom upstream data transfer apparatuses, and the data is transferred todownstream data transfer apparatuses connected to the selectedcommunication line. Thereby, the cost of installing in one exchangeoffice communication equipment compatible with each of these dissimilarcommunication protocols and the cost of constructing the networks can bereduced.

In addition, according to the present invention, in the edge routerapparatuses, information for switching the packets in each of the routerapparatuses positioned on the transfer path of the packets within thenetwork up to networks represented by destination addresses of thepackets is affixed to the to the packets in the transfer path order, atthe core router apparatuses, switching is carried out by using theswitching information affixed to the packet, and transfer is carried outafter deleting in sequence the used switching information. Thereby, inthe core routing apparatuses, it is not necessary to carry out a searchof the switching information, it is possible to reduce the processingload, and it becomes possible to increase the packet transferefficiency. As a result, it is possible to reduce the cost of thenetwork that includes the router apparatuses.

Furthermore, according to the present invention, for each of the othernetwork addresses, there is a routing table that stores the switchinginformation for switching the packets at each of the router apparatusespositioned on the transfer path of the packets in the network up to theother networks, and the switching information is found in this routingtable. Thus, it is possible to find the switching information simply,and it becomes possible to reduce the processing load. Thereby, it ispossible to reduce the cost of the network that includes routerapparatuses.

In addition, because the content of the routing table is set from thedata input apparatus, it becomes possible to carry out the setting ofthe routing table simply.

In addition, because the routing table is created after information hasbeen reported between router apparatuses, it becomes possible to carryout the setting of the routing table automatically.

1. A data transfer apparatus that receives data from an adjacentupstream data transfer apparatus and transfers the received data to anadjacent downstream data transfer apparatus, comprising: a datareception device that receives packets that comply to dissimilarcommunication protocols from the upstream data transfer apparatus; acontent data extraction device that extracts content data included in apacket received by the data reception device; a line selectioninformation storage device in which line selection information forselecting one of communication lines that comply with dissimilarcommunication protocols is stored; a line selection device that selectsa communication line corresponding to the content data extracted by thecontent data extraction device based on the line selection informationstored in the line selection information storage device; and a datatransfer device that transfers the packet to the downstream datatransfer apparatus that is connected to the communication line that hasbeen selected by the line selection device, wherein the content dataincludes virtual private network information that represents a virtualprivate network or logical line information that represents a logicalline, and in the case in which a packet which includes contents datahaving a value outside a range defined in the line selection informationstored in the line selection information storage device is input, in thecase in which a packet which includes contents data which does notinclude virtual private network information is input when the contentdata includes the virtual private network information, or in the case inwhich a packet which includes contents data which does not includelogical line information is input when the content data includes thelogical line information, the line selection device selects apredetermined communication line.
 2. A data transfer apparatus thatreceives data from an adjacent upstream data transfer apparatus andtransfers the received data to an adjacent downstream data transferapparatus, comprising: a data reception device that receives packetsthat comply to dissimilar communication protocols from the upstream datatransfer apparatus; a destination information extraction device thatextracts destination information that represents a destination includedin a packet that has been received by the data reception device; adestination selection information storage device that stores destinationselection information for selecting a communication line; a destinationline selection device that selects a communication line corresponding tothe destination information that has been extracted by the destinationinformation extraction device based on the destination selectioninformation that is stored in the destination information storagedevice; a content data extraction device that extracts content dataincluded in a packet received by the date reception device when aplurality of communication lines have been selected by the destinationline selection device; a line selection information storage device thatstores line selection information for selecting one of the communicationlines that comply with dissimilar communication protocols; a lineselection device that selects the communication line that has beenselected by the destination line selection device when the plurality ofcommunication lines have not been selected or selects a communicationline corresponding to the content data extracted by the content dataextraction device based on the line selection information stored in theline selection information storage device when the plurality ofcommunication lines have been selected; and a data transfer apparatusthat transfers the packet to the downstream data transfer apparatusconnected to the communication line that has been selected by the lineselection device, wherein the content data includes virtual privatenetwork information that represents a virtual private network or logicalline information that represents a logical line, and in the case inwhich a packet which includes contents data having a value outside arange defined in the line selection information stored in the lineselection information storage device is input, in the case in which apacket which includes contents data which does not include virtualprivate network information is input when the content data includes thevirtual private network information, or in the case in which a packetwhich includes contents data which does not include logical lineinformation is input when the content data includes the logical lineinformation, the line selection device selects a predeterminedcommunication line.
 3. A data transfer apparatus according to claim 2,further comprising: a packet analyzing device that analyzes the packetreceived by the data reception device when the destination informationextracted by the destination information extraction device representsits own address; and a line selection information updating device thatupdates the line selection information stored in the line selectioninformation storage device based on information that has been analyzedby the packet analyzing device.
 4. A data transfer apparatus accordingto claim 1, further comprising: a line selection information inputdevice that inputs the line selection information; and wherein: the lineselection information storage device stores the line selectioninformation input from the line selection information input device.
 5. Adata transfer apparatus according to claim 2, further comprising: a lineselection information input device that inputs the line selectioninformation; and wherein: the line selection information storage devicestores the line selection information input from the line selectioninformation input device.
 6. A data transfer apparatus according toclaim 3, further comprising: a line selection information input devicethat inputs the line selection information; and wherein: the lineselection information storage device stores the line selectioninformation input from the line selection information input device.
 7. Adata transfer apparatus according to any one of claims 1 through 6,wherein: the virtual private network information includes a VLANidentifier stipulated in IEEE 802.1Q.
 8. A data transfer apparatusaccording to any one of claims 1 through 6, wherein: the virtual privatenetwork information includes a VPN label that represents a VPNstipulated in RFC
 2547. 9. A data transfer apparatus according to anyone of claims 1 through 6, wherein: the virtual private networkinformation includes a VC label that represents a virtual circuitaffixed to a protocol data unit.
 10. A data transfer system, wherein: adata transfer apparatus according to any of claims 1 through 6 transfersdata to another data transfer apparatus according to any of claims 1through 6 according to a relay method.
 11. An edge router apparatus thatis disposed at a connection between a network and the outside of thenetwork, receives a packet from the outside of the network and transfersthe packet to a router apparatus within the network, or transmits apacket from a router within the network to the outside of the network,comprising: a switching information calculation device that obtainsswitching information for switching the received packet at each routerapparatus positioned along a transfer path of the received packet withinthe network based on a destination address of the packet received fromthe outside of the network; and a transmitting device that affixes tothe received packet the switching information obtained by the switchinginformation calculation device in a transfer path order starting from arouter apparatus subsequent to the edge router apparatus itself, andtransmits the received packet to which the switching information hasbeen affixed to a transfer destination router apparatus.
 12. An edgerouter apparatus that is disposed at a connection between a network andanother network, receives a packet from the other network and transfersthe packet to a router apparatus within the network, or transmits apacket from a router apparatus within the network to the other network,comprising: a routing table that stores switching information forswitching the packet at each router apparatus positioned along atransfer path of the packet in the network up to the other network foreach network address of the other network; a switching informationcalculation device that uses a destination address of the packetreceived from the other network, searches the routing table, and obtainsthe switching information for switching the received packet at eachrouter apparatus positioned along the transfer path of the receivedpacket within the network; and a transmitting device that affixes to thereceived packet the switching information obtained by the switchinginformation calculation device in a transfer path order starting from arouter apparatus subsequent to the edge router apparatus itself, andtransfers the received packet to which the switching information hasbeen affixed to a transfer destination router apparatus.
 13. An edgerouter apparatus according to claim 12, comprising: a data inputapparatus for setting the switching information in the routing table.14. A core router apparatus that receives and transfers a packet towhich switching information has been affixed for switching the packet,wherein: the core router apparatus switches the received packet based onthe top piece of a plurality of pieces of switching information whichare affixed to the received packet and are arranged in a transfer pathorder so as to correspond to router apparatuses which are arranged in apath from the core router apparatus itself to a network indicated by adestination address of the received packet, and the core routerapparatus comprises a transmitting device that deletes the top piece ofthe switching information used by the core router apparatus itself sothat the next piece of the switching information, which is to be used inthe switching by a router apparatus which is adjacent to the core routerapparatus itself, becomes the top piece of the switching information,and transmits the switched received packet to which the plurality ofpieces of switching information other than the top piece of theswitching information used by the core router apparatus itself areaffixed.
 15. A network system comprising: an edge router apparatus thatis disposed at a connection between a network and the outside of thenetwork, receives a packet from the outside of the network and transfersthe packet to a router apparatus within the network, or transmits apacket from a router within the network to the outside of the network;and a core router apparatus that receives and transfers a packet towhich switching information has been affixed for switching the packet;wherein: the edge router apparatus comprises: a switching informationcalculation device that obtains the switching information for switchingthe received packet at each router apparatus positioned along a transferpath of the received packet within the network based on a destinationaddress of the packet received from the outside of the network; and afirst transmitting device that affixes to the received packet theswitching information obtained by the switching information calculationdevice in a transfer path order starting from a router apparatussubsequent to the edge router apparatus itself, and transfers thereceived packet to which the switching information has been affixed to atransfer destination router apparatus; and the core router apparatuscomprises: a second transmitting device that switches the receivedpacket in the core router apparatus itself based on the switchinginformation that has been affixed to the received packet in a transferpath order starting from the core router apparatus itself, and transmitsa packet that has had the switching information used by the core routerapparatus itself deleted.
 16. A network system comprising: an edgerouter apparatus that is disposed at a connection between a network andan another network, receives a packet from the other network andtransfers the packet to a router apparatus within the network, ortransmits a packet from a router apparatus within the network to theother network; and a core router apparatus that receives and transfers apacket to which switching information has been affixed for switching thepacket; wherein: the edge router apparatus comprises: a routing tablethat stores switching information for switching the packet at eachrouter apparatus positioned along a transfer path of the packet in thenetwork up to the other network for each network address of the othernetwork; a switching information calculation device that uses adestination address of the packet received from the other network,searches the routing table, and obtains the switching information forswitching the received packet at each router apparatus positioned alongthe transfer path of the received packet within the network; and a firsttransmitting device that affixes to the received packet the switchinginformation obtained by the switching information calculation device ina transfer path order starting from a router apparatus subsequent to theedge router apparatus itself, and transfers the received packet to whichthe switching information has been affixed to a transfer destinationrouter apparatus; and the core router apparatus comprises: a secondtransmitting device that switches the received packet in the core routerapparatus itself based on the switching information that has beenaffixed to the received packet in a transfer path order starting fromthe core router apparatus itself, and transmits a packet that has hadthe switching information used by the core router apparatus itselfdeleted.
 17. A network system according to claim 16 wherein: the edgerouter apparatus provides a data input apparatus for setting theswitching information in the router table.
 18. A network systemaccording to claim 16, wherein: the edge router apparatus comprises: afirst reporting device that reports a network address of the othernetwork connected to the edge router apparatus itself and switchinginformation to the other network to a core router apparatus or anotheredge router apparatus connected to the edge router apparatus itself aspath information; and a creating device that receives the pathinformation that has been reported from the core router apparatus or theother edge router apparatus connected to the core router apparatusitself, and creates the routing table based on the received pathinformation; and the core router apparatus comprises: a second reportingdevice that affixes switching information for an edge router apparatusor a core router apparatus that have transmitted the path information tothe received path information, and reports the path information havingaffixed the switching information to core router apparatuses and edgerouter apparatuses other than the edge router apparatus and the corerouter apparatus that have transmitted the path information among corerouter apparatuses and edge router apparatuses that are connected to thecore router apparatus itself.